#include <iostream>
using namespace std;
struct nod {
    int info;
    struct nod *next,*prev;
};
typedef struct nod Tnod;
typedef Tnod *ref;

class ld
{
    ref nod_prim;
public:
    ld();
    ~ld();
    void Insd_P();
    void Insd_Cf();
    void readList();
    void print();
    ld operator+(Tnod);
    ld operator+(int);
    ld operator+(ld);
    bool operator==(ld);
    bool operator!=(ld);
};
